Hi, I am a new member. I am an electronic enthusiast and recently bought an ESR transistors tester http://www.ebay.com/itm/221390825755?_trksid=p2060778.m1438.l2648&ssPageName=STRK%3AMEBIDX%3AIT that I have used for a day or two and I think it is ok in general but the auto shutdown feature (25 seconds) is driving me crazy. I understand that feature extend the battery life which I don't care at all. I use the tester mainly looking for defective components on troubleshooting jobs. I wonder if there is someone out there that could help me turn off that feature or extend those 25 seconds to a longer time. Really appreciate any help.

Perhaps there is, but your chances of finding them on the Arduino forum are slim to none. I suggest you ask the vendor, or the manufacturer, or any forum that is closely related to the use of this type of instrument.

I only provide help via the forum - please do not contact me for private consultancy.

Well I came to Arduino Forum because the seller gave me no solution to my request and that instrument uses an ATmega 380p. That unit has a not programmable chip so I started my search and found a similar instrument but with the Atmega on a socket and you can found it at ( http://electronics-diy.com/esr-meter.php ). I used to program PICs and if I found help on how modify the ATmega 380 I will learn how to do the job. This will be beneficial to those that has one of these transistor testers and feels as I do. Thanks

Perhaps there is, but your chances of finding them on the Arduino forum are slim to none. I suggest you ask the vendor, or the manufacturer, or any forum that is closely related to the use of this type of instrument.

Interesting question.

Asking the vendor is clearly useless, as they simply sell the devices on from the manufacturer.

The manufacturer, in turn, is probably simply cloning a design from somewhere else, and any information they publish will likely be in Chinese.

Now the other and perhaps more relevant problem, is that I cannot find any reference in the Atmel literature to an ATmega 380p. Perhaps it is not made by Atmel?

What you said is absolutely right and looks like that's the standard now a day. I wonder if it's possible read from the microprocessor, interpreter the program, find the auto shutdown lines and alter the time or rem those lines instead and rewrite the program back. What do you think?

I wonder if it's possible read from the microprocessor, interpreter the program, find the auto shutdown lines and alter the time or rem those lines instead and rewrite the program back. What do you think?

Well, if you can tell me what the processor chip actually is, I might be in a better position to comment. I suspect it is in fact an AtMega328 variety because code libraries for these component detectors are available and presumably are what the (original) makers of these modules are using in which case they do not even have any reason to code-protect them. I have yet to buy one because I just keep bidding on them to see if I can get one for less than the "Buy it now" price. (It is rather humorous to see people bidding over the shelf price!) You have the more elegant graphic variety.

Reverse-engineering of the binary code if you can read it back from the device (using ISP) is not all that easy, it does not naturally fall out as source code which you can "REM", but it can be compared to the public-domain sources and if it matches, then it becomes easy.

What prevents an auto-shutdown? Is there some innocuous button ("Refresh Display") that you press to keep it going? You might be able to program an arduino to activate a relay every 12 seconds or so to keep it alive.

Paul__B:The processor is an Atmel Mega 328P AV1338 and the software, as the manufacture stated, is based on Markus F. design. Problem is I don't know if that chip could be reprogramming if it is not on a socket. I read on the Markus F. operational manual that the auto shutdown can be turned off by taking the transistor off the board and substitute it for a manual switch. I am not sure that I should do that not knowing if I can harm the tester.KeithRB:I have checked the board and can't find any other buttons that the Test and Off buttons. Maybe they don't use that approach. I took a pic of the board and perhaps that can give you an idea of what to do. Thanks

The board has the standard 10 pin In Circuit Programming connections, See near the AtMega where there are 2 rows of 5 pins with things like MISO MOSI and SCK next to them

If you connect and in circuit programmer to this you could try reading the program out of the chip, but this would only work if the Lock Bit that prevents reading had not been set.

If you can read the binary / machine code data, you can start to look for clues about where the timeout value may be stored and you may be able to write different numbers into the parts of the program that contains that data.

However this is not an easy thing to do, as all you will be looking at is a file full of numbers, and even if you managed to disassemble to Assembler code, things will not look much easier to understand, unless you are proficient in assembler programming.

If the whole device is just a clone of a open source project you could try finding downloading and compiling the original open source program and uploading it via the in circuit programmer and see if it works, but there would be no guarantee that the device would work, as they manufacturer may have made changes to the hardware from the original design etc etc

BTW. There is a separate section on device hacking on this forum, I know its sort of cross posting, but if you ask a specific question on their about how to read data from In Circuit port etc , I'm sure someone should be able to direct you to a usefull resource in that regard